In addition to its psychological (or phenomenological) analysis of numinous experiences, The Idea of the Holy also contains an apologetics, attempting to justify a subjectivist commitment to the Christian faith. In the tradition of German idealism, Otto assumes the dualism between the spiritual realm and the material realm. He frequently emphasizes that perceptions of the holy are a priori cognitions that are not based on experiences. For him, the spiritual realm includes emotional experiences that can be justified only on the basis of nonrational beliefs and intuitions. Although he writes that the capacity to perceive the holy is not innate, he asserts that every person has the potential to develop this capacity to some degree. Particular persons, moreover, like the Hebrew prophets and Jesus, are especially receptive to numinous revelations.
Otto uses the term divination to describe the psychological faculty for recognizing and cognizing the appearances of the holy. Profoundly influenced by Friedrich Schleiermacher’s theories of religious faith, which were based on “intuitions and feelings,” Otto assumes the existence of such a faculty, which presumably puts individuals in contact with a spiritual reality beyond themselves. Declaring that divination is comparable to aesthetic judgment, he writes that they are known by a “predisposing inner witness of the Spirit.” He acknowledges that his argument for intuitive religious experiences will not be convincing to “a person who is not prepared to take the religious consciousness itself for granted.”
Although respectful of other religious traditions, Otto writes that the “Christian religious feeling has given birth to a religious intuition profounder and more vital than any to be found in the whole history of religion.” He shows little interest in assessing the truth claims of cognitive beliefs, and his version of Christianity emphasizes morality as exemplified in the life and teachings of Jesus. The miracles of Jesus, whether or not they literally occurred, were primarily metaphors and signs of his “exalted spiritual powers over nature.” Otto reveals little about his personal beliefs about particular Christian doctrines, but he appears to be somewhat skeptical about the literal truthfulness of traditional doctrines such as the atonement, the Trinity, and individual consciousness in an otherworldly afterlife.